Method and system for detecting inter-cell short circuits in secondary batteries

Abstract

A method and system for detecting inter-cell short circuits in a secondary battery are disclosed. [Solution] A cell-to-cell short-circuit detection system for a secondary battery according to one embodiment of the present invention may include: a voltage measuring unit configured to include a probe that contacts the cells of the secondary battery and measures the voltage between the cells; a short-circuit control unit configured to control a short circuit between cells; and a cell-to-cell short-circuit detection unit configured to control the voltage measuring unit to measure a first voltage between a first cell and a second cell of the secondary battery, control the short-circuit control unit to cause a short circuit between the first cell and the second cell, control the voltage measuring unit to measure a second voltage between the first cell and the second cell, control the short-circuit control unit to eliminate the short circuit between the first cell and the second cell, control the voltage measuring unit to measure a third voltage between the first cell and the second cell, and determine whether or not a short circuit exists between the first cell and the second cell using at least one of the first voltage, the second voltage and the third voltage.

Description

Technical Field

[0001] The present invention relates to a method and a system for detecting an inter-cell short circuit of a secondary battery, and more particularly to a method and a system for detecting an inter-cell short circuit of a secondary battery by measuring a can-to-can voltage to determine the presence or absence of a short circuit between cells in a secondary battery module.

Background Art

[0002] Unlike a primary battery that cannot be charged, a secondary battery is a battery that can be charged and discharged. Small-capacity secondary batteries are used in portable small electronic devices such as smartphones, feature phones, notebook computers, digital cameras, and video cameras, and large-capacity secondary batteries are widely used in power sources for motor drives such as hybrid vehicles and electric vehicles, and batteries for power storage. Generally, a secondary battery assembles an electrode assembly with a separator interposed between a positive electrode, a negative electrode, and the positive electrode and the negative electrode. The assembled electrode assembly is mounted in a battery case, and an electrolyte is injected to manufacture a battery cell.

[0003] Among secondary batteries, lithium secondary batteries are utilized in various fields due to their excellent electrical characteristics. However, lithium secondary batteries have a problem of low safety. For example, a lithium secondary battery may catch fire or explode in an abnormal operating state such as overcharging, over-discharging, exposure to high temperature, or an electrical short circuit. Specifically, active materials or electrolytes, which are components of a battery cell, undergo a decomposition reaction to generate heat and gas. The generated heat and gas increase the temperature and pressure inside the battery cell. The increased temperature and pressure further promote the decomposition reaction, and eventually, fire or explosion may occur.

[0004] Therefore, it is very important to ensure the safety of battery cells, and one of the methods is to evaluate the safety of battery cells when an inter-cell short circuit occurs. In particular, there is a need for a technique to determine the presence or absence of an inter-cell short circuit.

[0005] Conventional methods for detecting short circuits between battery cells include voltage withstand measurement, resistance measurement, and voltage measurement. However, the voltage withstand (insulation resistance) measurement method cannot detect leakage current (short) between cells because it measures the leakage current when a high voltage is applied to the module. The resistance measurement method has reliability issues because large variations occur when measuring resistance due to the electromotive force of the battery. The cell voltage measurement method can only detect a cell voltage drop caused by a short circuit between cells by measuring the voltage between cell terminals, and since it takes several months or more for the cell voltage drop to occur due to the short-circuit resistance between cells, there is a problem that detection takes a long time.

[0006] The information disclosed above in the background art of such inventions is merely for the purpose of improving the understanding of the background of the present invention, and therefore may include information that does not constitute prior art. [Overview of the project] [Problems that the invention aims to solve]

[0007] The problem that this invention aims to solve is a method and system for detecting inter-cell short circuits in a secondary battery, which measures the can-to-can voltage based on changes in state caused by metallic foreign objects (unique objects) during the assembly of the secondary battery module, and determines whether or not there is a short circuit between cells.

[0008] However, the technical problems that the present invention aims to solve are not limited to those described above, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention below. [Means for solving the problem]

[0009] The inter-cell short-circuit detection system of a secondary battery according to an embodiment of the present invention includes a voltage measurement unit configured to include a probe that contacts a cell of the secondary battery and measures the voltage between cells, a short-circuit control unit configured to control a short between cells, and a voltage measurement unit to control to measure a first voltage between a first cell and a second cell of the secondary battery, control the short-circuit control unit to generate a short between the first cell and the second cell, control the voltage measurement unit to measure a second voltage between the first cell and the second cell, control the short-circuit control unit to remove the short between the first cell and the second cell, control the voltage measurement unit to measure a third voltage between the first cell and the second cell, and determine the presence or absence of a short between the first cell and the second cell using at least one of the first voltage, the second voltage, and the third voltage.

[0010] In one embodiment, the inter-cell short-circuit detection unit can determine the presence or absence of a short between the first cell and the second cell based on whether the second voltage corresponds to a preset cell voltage reference.

[0011] In one embodiment, the inter-cell short-circuit detection unit can determine the presence or absence of a short between the first cell and the second cell based on whether the difference between the first voltage and the second voltage corresponds to a preset cell voltage reference.

[0012] In one embodiment, the inter-cell short-circuit detection unit can determine the presence or absence of a short between the first cell and the second cell based on whether the difference between the third voltage and the second voltage corresponds to a preset cell voltage reference.

[0013] In one embodiment, the probe may be configured in an "L" shape.

[0014] In one embodiment, the probe may be configured in a "V" shape.

[0015] In one embodiment, the probe may be configured in a "W" shape.

[0016] In one embodiment, the voltage measuring unit may further include a pressure sensor configured to adhere to one surface of the probe and measure the pressure applied to that surface, and a probe control unit configured to control the operation of the probe and to control the operation of the probe so that the probe contacts the cell at a preset pressure or less.

[0017] In one embodiment, the probe control unit can control the movement of the probe so that it passes through the CMC hole of the can constituting the cell and comes into contact with the cap plate.

[0018] In one embodiment, the short-circuit control unit can generate a short circuit by adding a specific resistor between the first cell and the second cell.

[0019] A method for detecting inter-cell short circuits in a secondary battery according to one embodiment of the present invention is a method driven by an inter-cell short circuit detection system for a secondary battery, which includes a voltage measuring unit configured to include a probe that contacts the cells of the secondary battery to measure the voltage between the cells, and a short circuit control unit configured to control the short circuit between the cells, and the method may include: controlling the voltage measuring unit to measure a first voltage between a first cell and a second cell of the secondary battery; controlling the short circuit control unit to cause a short circuit between the first cell and the second cell; controlling the voltage measuring unit to measure a second voltage between the first cell and the second cell; controlling the short circuit control unit to eliminate the short circuit between the first cell and the second cell; controlling the voltage measuring unit to measure a third voltage between the first cell and the second cell; and determining whether or not there is a short circuit between the first cell and the second cell using at least one of the first voltage, the second voltage, and the third voltage.

[0020] In one embodiment, the inter-cell short-circuit detection step can determine whether or not a short circuit exists between the first cell and the second cell based on whether or not the second voltage corresponds to a preset cell voltage reference.

[0021] In one embodiment, the inter-cell short-circuit detection step can determine the presence or absence of a short circuit between the first cell and the second cell based on whether the difference between the first voltage and the second voltage corresponds to a preset cell voltage reference.

[0022] In one embodiment, the inter-cell short-circuit detection step can determine the presence or absence of a short circuit between the first cell and the second cell based on whether the difference between the third voltage and the second voltage corresponds to a preset cell voltage reference.

[0023] In one embodiment, the probe may be configured in an "L" shape.

[0024] In one embodiment, the probe may be configured in a "V" shape.

[0025] In one embodiment, the probe may be configured in a "W" shape.

[0026] In one embodiment, the voltage measurement unit further includes a pressure sensor configured to adhere to one surface of the probe and measure the pressure applied to one surface of the probe, and a probe control unit configured to control the operation of the probe, and the voltage measurement step can control the operation of the probe by controlling the probe control unit so that the probe contacts the cell at a pressure below a preset pressure.

[0027] In one embodiment, the voltage measurement step can control the operation of the probe by controlling the probe control unit so that the probe passes through the CMC hole of the can that constitutes the cell and contacts the cap plate.

[0028] In one embodiment, the short-circuit generation step can control the short-circuit control unit to add a specific resistance between the first cell and the second cell.

Advantages of the Invention

[0029] According to one embodiment of the present invention, when a short circuit occurs between cells, it is possible to clearly distinguish whether or not a short circuit has occurred between cells, the possibility of detection errors is very low, and the reliability of the detection results can be guaranteed.

[0030] According to one embodiment of the present invention, there is an advantage in that a short circuit between cells can be detected regardless of the magnitude of the short-circuit resistance between cells.

[0031] According to one embodiment of the present invention, it has the advantage of being usable not only as an inspection method for assembled secondary battery modules, but also as an inspection method for in-line processes.

[0032] According to one embodiment of the present invention, inspection can be performed using a simple measuring device without the need for a charger / discharger, and the time and cost required to detect short circuits between cells can be reduced.

[0033] However, the effects that can be obtained by the present invention are not limited to those described above, and other technical effects not mentioned will be clearly understood by those skilled in the art from the description of the invention below. [Brief explanation of the drawing]

[0034] The following drawings attached to this application illustrate preferred embodiments of the present invention and, together with the detailed description of the invention later, serve to provide a better understanding of the technical concept of the present invention. Therefore, the present invention should not be interpreted as being limited only to the matters described in these drawings. [Figure 1A] This is a top perspective view of a rectangular rechargeable battery. [Figure 1B] This is a cross-sectional view of line I-I' in Figure 1A. [Figure 2] This is a block diagram of a cell-to-cell short-circuit detection system according to an embodiment of the present invention. [Figure 3] This figure shows a cell-to-cell short-circuit detection system implemented according to an embodiment of the present invention. [Figure 4] This figure shows a cell-to-cell short-circuit detection system implemented according to an embodiment of the present invention. [Figure 5] This figure shows a cell-to-cell short-circuit detection system implemented according to an embodiment of the present invention. [Figure 6] This is a circuit diagram demonstrating a short circuit between cells according to an embodiment of the present invention. [Figure 7] This is a block diagram of a voltage measurement unit according to an embodiment of the present invention. [Figure 8] These are a front view and a side view showing a probe according to the first embodiment of the present invention. [Figure 9] These are a front view and a side view showing a probe according to a second embodiment of the present invention. [Figure 10] These are a front view and a side view showing a probe according to a third embodiment of the present invention. [Figure 11] This is a side view showing cell voltage measurement of a probe according to a third embodiment of the present invention. [Figure 12] This is a flowchart illustrating a method for detecting inter-cell short circuits in a secondary battery according to one embodiment of the present invention. [Modes for carrying out the invention]

[0035] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Prior to this, terms and words used herein and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but in accordance with the principle that inventors may appropriately define the concepts of terms in order to best describe their invention, and should be interpreted in a manner consistent with the technical idea of ​​the present invention. Accordingly, the embodiments described herein and the configurations shown in the drawings represent only some of the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and it should be understood that there are a variety of equivalents and modifications that can be substituted for them at the time of filing.

[0036] Furthermore, as used herein, “comprise, include” and / or “comprising, including” identify the presence of the shape, figure, stage, action, member, element, and / or group thereof mentioned, and do not exclude the presence or addition of one or more other shapes, figures, actions, members, elements, and / or groups thereof.

[0037] Furthermore, for the sake of understanding the invention, the attached drawings are not shown to actual scale, and the dimensions of some components may be exaggerated. Also, identical components may be assigned the same reference numeral in different embodiments.

[0038] The statement that two comparison subjects are "identical" means that they are "substantially identical." Therefore, substantially identical subjects may have deviations that are considered low in this industry, for example, deviations of 5% or less. Also, the statement that a parameter is uniform in a given area can mean that it is uniform from an average perspective.

[0039] For example, terms like "first," "second," etc., are used to describe various components, but it goes without saying that these components are not limited by these terms. These terms are simply used to distinguish one component from another, and unless otherwise stated, the first component may be the second component.

[0040] Throughout the specification, unless otherwise stated, each component may be singular or plural.

[0041] The placement of any configuration "above (or below)" a component or "above (or below)" a component can mean not only that the configuration is placed in contact with the upper (or lower) surface of the component, but also that other configurations may be interposed between the component and any configuration placed above (or below) it.

[0042] Furthermore, when a component is described as being "on," "connected to," or "coupled to" another component, it should be understood that while the components may be directly connected to each other, other components may be "interposed" between them, or components may be "connected," "coupled," or "linked" through other components.

[0043] As used herein, the terms "and / or" include any and all combinations of one or more of the items listed relating to the invention. Furthermore, when describing embodiments of the invention, the use of "may also apply" applies to "one or more embodiments of the invention." Expressions such as "one or more" preceding an element list modify the entire element list, not individual elements of the list.

[0044] Throughout the specification, "A and / or B" means A, B, or A and B unless otherwise specified, and "C to D" means C or greater and D or less unless otherwise specified.

[0045] When syntax such as "at least one of A, B, and C", "at least one of A, B, or C", "at least one selected from the group A, B, and C", or "at least one selected from among A, B, and C" is used to specify a list of elements A, B, and C, the syntax can refer to any suitable combination.

[0046] The term “use” is considered synonymous with the term “utilize.” Terms such as “substantially,” “about,” and similar terms as used herein are used as approximations, not terms of degree, to account for the inherent variability of measured or calculated values ​​as perceived by a general arter in the relevant art.

[0047] In this specification, terms such as first, second, third, etc., are used to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, drawing layer, or section from other elements, components, regions, drawing layers, or sections. Accordingly, the first elements, components, regions, layers, or sections discussed below may be named second elements, components, regions, layers, or sections, to the extent that they do not deviate from the teachings of the exemplary embodiments.

[0048] As illustrated, in describing the relationship between one element or feature and another, spatially relative terms such as “beneath,” “below,” “lower,” “above,” and “upper” are used in the specification for ease of explanation. Spatially relative positions will be understood to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the figure. For example, if the device in the drawing is turned upside down, the other elements will be understood as “below” or “below,” and the described element as “above” or “upper” of the other elements. Thus, the term “below” can encompass both up and down directions.

[0049] The terms used herein are for describing embodiments of the present invention and are not intended to limit the invention.

[0050] The present invention will be described in detail below with reference to the attached drawings.

[0051] Rechargeable batteries come in various types, including coin-type, cylindrical, prismatic, and pouch-type. Since the present invention is basically applicable to prismatic rechargeable batteries, we will first briefly describe prismatic rechargeable batteries before describing embodiments of the present invention.

[0052] Figure 1A is a top perspective view of a prismatic secondary battery, and Figure 1B is a cross-sectional view taken along line I-I' in Figure 1A.

[0053] First, let's describe the appearance of the rectangular rechargeable battery shown in Figure 1A.

[0054] The case 51 forms the overall appearance of the prismatic secondary battery and is made of a conductive metal such as aluminum, aluminum alloy, or nickel-plated steel. The case 51 can also provide space for housing the electrode assembly.

[0055] The cap assembly 60 may include a cap plate 61 that covers the opening of the case 51, and both the case 51 and the cap plate 61 are made of a conductive material. Here, the first terminal 62 and the second terminal 63 are electrically connected to an internal positive or negative electrode and are provided so as to penetrate the cap plate 61 and protrude outward.

[0056] The cap plate 61 has an electrolyte inlet 64 with a sealing plug and a vent 66 with a notch 65. The vent 66 is for degassing gas generated from inside the battery.

[0057] Referring to Figure 1B, the internal structure of the prismatic secondary battery and its connection structure with the cap assembly 60 will be described.

[0058] The rectangular secondary battery shown in Figure 1B basically includes an electrode assembly 40, a first current collector 41, a first terminal 62, a second current collector 42, a second terminal 63, and a cap assembly 60.

[0059] The electrode assembly 40 is formed by winding or stacking a laminate of a first electrode plate, a separator, and a second electrode plate, which are formed in a plate-like or film-like shape. In the case of a wound laminate, the winding axis of the electrode assembly 40 may be parallel to the longitudinal direction of the case. The electrode assembly 40 may also be a stack type rather than a wound type, but the shape of the electrode assembly 40 is not limited in this invention. The electrode assembly 40 may also be a Z-stack electrode assembly in which the first electrode plate and the second electrode plate are inserted on both sides of a separator bent into a Z-stack. Furthermore, the electrode assembly 40 may be one or more electrode assemblies stacked so that their long sides are adjacent to each other and housed inside the case, and the number of electrode assemblies is not limited in this invention. The first electrode plate of the electrode assembly 40 can play the role of a negative electrode, and the second electrode plate can play the role of a positive electrode, and vice versa.

[0060] The first electrode plate is formed by coating a first electrode active material, such as graphite or carbon, onto a first electrode current collector plate made of a metal foil such as copper, a copper alloy, nickel, or a nickel alloy, and may include a first electrode tab (or first blank area) which is an area where the first electrode active material is not coated. The first electrode tab 43 serves as a current passage between the first electrode plate and the first current collector 41. In some examples, the first electrode tab 43 can be formed by cutting it in advance to protrude from one side when manufacturing the first electrode plate, and can protrude further from the separator on one side without further cutting.

[0061] The second electrode plate is formed by coating a second electrode active material, such as a transition metal oxide, onto a substrate made of a metal foil, such as aluminum or an aluminum alloy, and may include a second electrode tab (or second blank area) 44, which is an area where the second electrode active material is not coated. The second electrode tab 44 serves as a current passage between the second electrode plate and the second current collector 42. In some examples, the second electrode tab 44 can be formed by cutting it in advance to protrude to the other side when manufacturing the second electrode plate, and can protrude further to the other side of the separator without further cutting.

[0062] In some embodiments, the first electrode tab 43 may be located on the right-side edge of the electrode assembly 40, and the second electrode tab 44 may be located on the left-side edge of the electrode assembly 40, or on one side in the same direction. Here, the left, right, and top are for illustrative purposes only, based on the secondary battery shown in Figure 2B, and their positions can be changed when the secondary battery rotates left / right or up / down.

[0063] The separator functions to prevent short circuits between the first electrode plate and the second electrode plate while allowing the movement of lithium ions. The separator is made of, for example, polyethylene film, polypropylene film, polyethylene-polypropylene film, etc.

[0064] The electrode assembly 40 described above has first electrode tabs 43 for the first electrode plate and second electrode tabs 44 for the second electrode plate extending from both ends. In some embodiments, the electrode assembly 40 is housed in a case 51 together with the electrolyte.

[0065] In the electrode assembly 40, the first electrode tab 43 and the second electrode tab 44, which extend from the first electrode plate and the second electrode plate on both sides, can be welded to the first current collector 41 and the second current collector 42, respectively.

[0066] The first current collector 41 and the second current collector 42 are connected to the first terminal 62 and the second terminal 63, respectively, as described in Figure 1A, via a connecting column 67. In some embodiments, the outer surface of the connecting column 67 may be threaded, and it can be fastened to the first terminal 62 and the second terminal 63 by screw connection. However, the present invention is not limited thereto, and the connecting column 67 may be connected to the first terminal 62 and the second terminal 63 by riveting or welding.

[0067] Figure 2 is a block diagram of an inter-cell short-circuit detection system 10 according to an embodiment of the present invention.

[0068] Referring to Figure 2, the inter-cell short-circuit detection system 10 according to an embodiment of the present invention may include an inter-cell short-circuit detection unit 100, a voltage measurement unit 200, and a short-circuit control unit 300.

[0069] The inter-cell short-circuit detection unit 100 can control the voltage measurement unit 200 and the short-circuit control unit 300 to determine whether or not there is a short circuit between the cells of the secondary battery.

[0070] The inter-cell short-circuit detection unit 100 may include a communication unit 110, an input unit 120, a display unit 130, a memory 140, and a control unit 150.

[0071] The communication unit 110 can communicate with user or administrator terminals via network communication and can communicate with a server that controls the inter-cell short-circuit detection system 10. For this purpose, the communication unit 110 can perform internet communication such as 5G (5th generation), LTE-A (long term evolution-advanced), LTE (long term evolution), and Wi-Fi (wireless fidelity) (registered trademark).

[0072] The input unit 120 generates input data in response to administrator input for managing the inter-cell short-circuit detection system 10. In particular, the input unit 120 can receive from the administrator the specifications of the secondary battery for which inter-cell short circuits are to be detected, the operation control signals of the probe 230 (described later), and so on. For this purpose, the input unit 120 may include a key pad, a dome switch, a touch panel, touch keys, and buttons.

[0073] The display unit 130 outputs output data based on the operation of the inter-cell short-circuit detection system 10. In particular, the display unit 130 can display the current status regarding the presence or absence of a short circuit between cells of the secondary battery detected by the inter-cell short-circuit detection system 10, and information about the cell in which the short circuit occurred. For this purpose, the display unit 130 may include a liquid crystal display (LCD), a light-emitting diode (LED) display, an organic light-emitting diode (OLED) display, a micro-electro-mechanical systems (MEMS) display, and an electronic paper display.

[0074] The memory 140 stores the operating program for the inter-cell short-circuit detection system 10. In particular, the memory 140 can store an algorithm that allows the control unit 150 to determine whether or not there is a short circuit between cells, reference information for determining whether or not there is a short circuit between cells, an algorithm for controlling the operation of the voltage measurement unit 200, and an algorithm for controlling the operation of the short-circuit control unit 300.

[0075] The control unit 150 can control the communication unit 110, the input unit 120, the display unit 130, and the memory 140, and the control unit 150 can control the voltage measurement unit 200 and the short-circuit control unit 300 to determine whether or not there is a short circuit between the cells of the secondary battery.

[0076] For this purpose, the control unit 150 can control the voltage measuring unit 200 to measure the first voltage between the first and second cells of the secondary battery. The first voltage is the measured voltage of a normal module where there are no foreign objects between the first and second cells.

[0077] The control unit 150 can control the short-circuit control unit 300 to generate a short circuit between the first and second cells of the secondary battery. The method by which the short-circuit control unit 300 generates a short circuit between the first and second cells will be described later. This makes it possible to simulate the secondary battery as a defective module with foreign matter between the first and second cells.

[0078] The control unit 150 can control the voltage measuring unit 200 to measure the second voltage between the first and second cells of the secondary battery. The second voltage is the measured voltage of a defective module where there is foreign matter between the first and second cells.

[0079] The control unit 150 can control the short-circuit control unit 300 to eliminate the short circuit between the first and second cells of the secondary battery. This makes the secondary battery appear as a normal module with no foreign matter between the first and second cells.

[0080] The control unit 150 can control the voltage measuring unit 200 to measure a third voltage between the first and second cells of the secondary battery. The third voltage is the measured voltage of a normal module from which foreign matter has been removed between the first and second cells.

[0081] The control unit 150 can determine whether or not there is a short circuit between the first cell and the second cell using at least one of the first voltage, the second voltage, and the third voltage.

[0082] According to an embodiment of the present invention, the control unit 150 can determine whether or not there is a short circuit between the cells of the secondary battery by various determination methods.

[0083] As a first embodiment of the present invention, the control unit 150 can determine whether or not there is a short circuit between cells based on whether or not the second voltage meets the detection criteria. The control unit 150 can determine that there is a short circuit between the first cell and the second cell if the second voltage is less than the reference cell voltage. The reference cell voltage can be set according to the State of Charge (SOC), and as an example, it can be set to 3.5V for SOC30 and 3.7V for SOC50. However, this is just an example, and the reference cell voltage can be set in various ways depending on the state of the secondary battery. Therefore, the control unit 150 can determine that there is no short circuit between the first cell and the second cell if the second voltage is the cell reference voltage.

[0084] In a second embodiment of the present invention, the control unit 150 can determine whether or not there is a short circuit between cells based on whether or not the difference between the first voltage and the second voltage meets the detection criteria. The control unit 150 can determine that there is a short circuit between the first cell and the second cell if the difference between the first voltage and the second voltage is less than the reference cell voltage. The reference cell voltage can be set according to the SOC (State of Charge), and as mentioned above, it can be set to 3.5V for SOC30 and 3.7V for SOC50. Therefore, the control unit 150 can determine that there is no short circuit between the first cell and the second cell if the difference between the first voltage and the second voltage is equal to the cell reference voltage.

[0085] In a third embodiment of the present invention, the control unit 150 can determine whether or not there is a short circuit between cells based on whether or not the difference between the third voltage and the second voltage meets the detection criteria. The control unit 150 can determine that there is a short circuit between the first cell and the second cell if the difference between the third voltage and the second voltage is less than the reference cell voltage. The reference cell voltage can be set according to the SOC (State of Charge), and as mentioned above, it can be set to 3.5V for SOC30 and 3.7V for SOC50. Therefore, the control unit 150 can determine that there is no short circuit between the first cell and the second cell if the difference between the third voltage and the second voltage is the cell reference voltage.

[0086] The control unit 150 can determine whether or not there is a short circuit between the first cell and the second cell using one of the first to third embodiments of the present invention described above, and can also determine whether or not there is a short circuit between the first cell and the second cell using a combination of the first to third embodiments.

[0087] The control unit 150 can control the display unit 130 to output the short-circuit detection result between the first cell and the second cell.

[0088] The control unit 150 can determine and output whether there is a short circuit between the second and third cells of the secondary battery, and between the third and fourth cells, etc., using the method described above. By determining whether there is a short circuit between all the cells of the secondary battery, it can ultimately detect a short circuit between the cells of the secondary battery.

[0089] Furthermore, the control unit 150 can control the operation of the voltage measurement unit 200 and the short-circuit control unit 300.

[0090] The voltage measurement unit 200 can measure the voltage between cells in a secondary battery. A detailed explanation of the voltage measurement unit 200 will be provided in Figure 7 and subsequent figures.

[0091] The short-circuit control unit 300 can generate or eliminate short circuits between cells in the secondary battery.

[0092] The short-circuit control unit 300 can generate short circuits between cells in various ways. In one embodiment of the present invention, the short-circuit control unit 300 can generate short circuits between cells by adding a specific resistor between the cells of a secondary battery. For example, the short-circuit control unit 300 can configure the resistor added between the cells of the secondary battery to be between 0.3Ω and 5kΩ. Conversely, the short-circuit control unit 300 can remove the resistor added between the cells of the secondary battery to eliminate the short circuit between cells.

[0093] As mentioned above, the cells of the secondary battery are made up of a can, and the can may be made up including an external insulator. The short-circuit control unit 300 can generate a short by connecting the resistor added between the cells to a can from which the external insulation has been completely removed, or it can generate a short by connecting it to a can from which the external insulation has been partially removed.

[0094] Figures 3 to 5 show a realization of the inter-cell short-circuit detection system 10 according to an embodiment of the present invention.

[0095] Referring to Figure 3, the inter-cell short-circuit detection system 10 according to an embodiment of the present invention includes an inter-cell short-circuit detection unit 100 and a voltage measurement unit 200, the voltage measurement unit 200 being connectable to all cells of the secondary battery. Since the voltage measurement unit 200 is connected to all cells of the secondary battery, the inter-cell short-circuit detection unit 100 can control the voltage measurement unit 200 to measure the desired voltage between cells.

[0096] Referring to Figures 4 and 5, the voltage measurement unit 200 according to an embodiment of the present invention may include a switch unit (not shown). The inter-cell short-circuit detection unit 100 can easily measure the voltage between cells by controlling the switch unit (not shown).

[0097] A switch unit (not shown) can control the connection between the secondary battery cells and the voltage measurement unit 200. The switch unit (not shown) can control the connection between the secondary battery cells and the voltage measurement unit 200 by controlling the inter-cell short-circuit detection unit 100, thereby measuring the desired voltage between cells.

[0098] As shown in Figure 4, in order to measure the voltage between the first and second cells, the switch unit (not shown) can connect the voltage measuring unit 200 to the first and second cells and disconnect it from the remaining cells.

[0099] As shown in Figure 5, in order to measure the voltage between the second and third cells, the switch unit (not shown) can connect the voltage measuring unit 200 to the second and third cells and disconnect the voltage measuring unit 200 from the remaining cells.

[0100] Figure 6 is a circuit diagram showing a short circuit between cells according to an embodiment of the present invention.

[0101] Figure 6(a) is a circuit diagram of a normal module with no short circuits between the cells of the secondary battery, while Figure 6(b) is a circuit diagram of a defective module with short circuits between the cells of the secondary battery. As shown in Figure 6(b), a short circuit can be created between the cells by adding a specific resistor between the cells of the secondary battery.

[0102] As described above, the short-circuit control unit 300 can create or eliminate short circuits between cells in a secondary battery. The short-circuit control unit 300 can create short circuits between cells by adding a specific resistor between the cells of the secondary battery. For example, the short-circuit control unit 300 can configure the resistor added between the cells of the secondary battery to be between 0.3Ω and 5kΩ. Conversely, the short-circuit control unit 300 can eliminate short circuits between cells by removing the resistor added between the cells of the secondary battery. The cells of the secondary battery are made up of cans, and the cans may be made up including an external insulator. The short-circuit control unit 300 can create a short circuit by connecting the resistor added between cells to a can with the external insulation completely removed, or it can create a short circuit by connecting it to a can with the external insulation partially removed.

[0103] Figure 7 is a block diagram of the voltage measuring unit 200 according to an embodiment of the present invention.

[0104] Referring to Figure 7, the voltage measuring unit 200 according to an embodiment of the present invention may include a pressure sensor 210, a probe control unit 220, and a probe 230.

[0105] The pressure sensor 210 can be attached to one surface of the probe 230 and measure the pressure applied to that surface of the probe 230. The pressure sensor 210 can transmit the measured pressure information of the probe 230 to the probe control unit 220.

[0106] The probe control unit 220 can control the operation of the probe 230. The probe control unit 220 can control the drive of the probe 230 so that the probe 230 makes contact with the cells of the secondary battery. Specifically, the probe control unit 220 can control the probe 230 so that it makes contact with the cans that make up the cells of the secondary battery, and so that the voltage between the cells can be measured.

[0107] The probe control unit 220 can control the operation of the probe 230 using the pressure information of the probe 230 input via the pressure sensor 210. In other words, the probe control unit 220 can control the drive of the probe 230 so that the probe 230 does not come into contact with the secondary battery cell casing if the pressure exceeds a certain level. This makes it possible to measure the voltage between cells of a secondary battery without damaging the secondary battery cell casing even if it comes into contact with it.

[0108] The probe 230 can contact the cells of a secondary battery and measure the voltage between the cells. The probe 230 may consist of at least two probes, with the first probe 230 being able to contact the first cell of the secondary battery and the second probe 230 being able to contact the second cell of the secondary battery. This allows the probe 230 to measure the voltage between the first and second cells.

[0109] The probe 230 is capable of contacting the casing of the secondary battery cells for voltage measurement; specifically, the probe 230 is capable of contacting the cap plate through the CMC hole in the casing. This allows the voltage between cells to be measured by crimping the probe 230 to the cells without removing the outer insulator at the bottom of the cells.

[0110] The probe 230 may be configured in various shapes to easily contact the cell. That is, the probe 230 may be configured in a shape that is efficient for passing through the CMC hole of the secondary battery cell and contacting the cap plate. Hereinafter, various embodiments of the shape of the probe 230 will be described.

[0111] FIG. 8 is a front view and a side view showing a probe 231 according to a first embodiment of the present invention. Referring to FIG. 8, one surface of the probe 231 according to the first embodiment of the present invention that contacts the cell may be configured in an "L" shape.

[0112] After passing the probe 231 according to the first embodiment through the CMC hole of the secondary battery cell, the probe control unit 220 can be driven to move left and right to contact the cap plate.

[0113] FIG. 9 is a front view and a side view showing a probe 232 according to a second embodiment of the present invention. Referring to FIG. 9, one surface of the probe 232 according to the second embodiment of the present invention that contacts the cell may be configured in a "V" shape.

[0114] After passing the probe 232 according to the second embodiment through the CMC hole of the secondary battery cell, the probe control unit 220 can be driven to tilt left and right to contact the cap plate.

[0115] FIG. 10 is a front view and a side view showing a probe 233 according to a third embodiment of the present invention. Referring to FIG. 10, one surface of the probe 233 according to the third embodiment of the present invention that contacts the cell may be configured in a "Λ" shape.

[0116] After passing the probe 233 according to the third embodiment through the CMC hole of the secondary battery cell, the probe control unit 220 can be driven to move up and down to contact the cap plate.

[0117] Figure 11 is a side view showing cell voltage measurement of probe 233 according to the third embodiment of the present invention. Referring to Figure 11, as described above, under the control of the probe control unit 220, the probe 233 according to the third embodiment of the present invention appears to move up and down after passing through the CMC hole of the secondary battery cell and then coming into contact with the cap plate. The probe 233 according to the third embodiment may be configured such that the angle of the "human" shape increases as it comes into contact with the cap plate.

[0118] Figure 12 is a flowchart illustrating a method for detecting inter-cell short circuits in a secondary battery according to one embodiment of the present invention.

[0119] Referring to Figure 12, a method for detecting inter-cell short circuits in a secondary battery according to one embodiment of the present invention may include steps S100 to S160.

[0120] Step S100 is a step in which the inter-cell short-circuit detection unit 100 controls the voltage measurement unit 200 to measure a first voltage between the first cell and the second cell.

[0121] Step S110 is a step in which the inter-cell short-circuit detection unit 100 controls the short-circuit control unit 300 to cause a short circuit between the first cell and the second cell.

[0122] Step S120 is a step in which the inter-cell short-circuit detection unit 100 controls the voltage measurement unit 200 to measure the second voltage between the first cell and the second cell.

[0123] Step S130 is a step in which the inter-cell short-circuit detection unit 100 controls the short-circuit control unit 300 to eliminate the short circuit between the first cell and the second cell.

[0124] Step S140 is a step in which the inter-cell short-circuit detection unit 100 controls the voltage measurement unit 200 to measure the third voltage between the first cell and the second cell.

[0125] Step S150 is a step in which the cell-to-cell short-circuit detection unit 100 determines whether or not there is a short circuit between the first cell and the second cell using at least one of the first voltage, the second voltage, and the third voltage.

[0126] Step S160 is a step in which the inter-cell short-circuit detection unit 100 controls the display unit 130 to output the short-circuit detection result between the first cell and the second cell.

[0127] The method for detecting inter-cell short circuits in a secondary battery according to one embodiment of the present invention, as described above, was explained with reference to the flowchart shown in the drawings. For the sake of brevity, the method was illustrated and explained in a series of blocks, but the present invention is not limited to the order of the blocks, and some blocks may occur in a different order or simultaneously with other blocks than those illustrated and described herein, and a variety of other branches, flow paths, and block orders may be realized to achieve the same or similar results. Furthermore, not all illustrated blocks are required to implement the method described herein.

[0128] On the other hand, in the description with reference to Figure 12, each step may be further divided into additional steps or combined into fewer steps according to the embodiment of the present invention. Also, some steps may be omitted as needed, and the order between steps may be changed. In addition, even if other details are omitted, the contents of Figures 1A to 11 are applicable to the contents of Figure 12. Furthermore, the contents of Figure 12 are applicable to the contents of Figures 1A to 11.

[0129] The following describes materials that can be used in the secondary battery according to the present invention.

[0130] As the positive electrode active material, compounds capable of reversible intercalation and deintercalation of lithium (lithiated intercalation compounds) can be used. Specifically, one or more composite oxides of lithium with metals selected from cobalt, manganese, nickel, and combinations thereof can be used.

[0131] The aforementioned composite oxide may be a lithium transition metal composite oxide, and specific examples include lithium nickel oxide, lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate compound, cobalt-free nickel-manganese oxide, or a combination thereof.

[0132] As an example, compounds represented by any one of the following chemical formulas can be used: LiaA1-bXbO2-cDc(0.90≦a≦1.8, 0≦b≦0.5, 0≦c≦0.05);LiaMn2-bXbO4-cDc(0.90≦a≦1.8, 0≦b≦0.5, 0≦c≦0.05);LiaNi1-b-cCobXcO2-αDα(0.90≦a≦1.8, 0≦b≦0.5, 0≦c≦0.5, 0<α<2);LiaNi1-b-cMnbXcO2-αDα(0.90≦a≦1.8, 0≦b≦0.5, 0≦c≦0.5, 0<α<2);LiaNibCocL1dGeO2( 0.90≦a≦1.8, 0≦b≦0.9, 0≦c≦0.5, 0≦d≦0.5, 0≦e≦0.1);LiaNiGbO2(0 .90≦a≦1.8, 0.001≦b≦0.1);LiaCoGbO2(0.90≦a≦1.8, 0.001≦b≦0.1 );LiaMn1-bGbO2(0.90≦a≦1.8, 0.001≦b≦0.1);LiaMn2GbO4(0.90≦ a≦1.8, 0.001≦b≦0.1);LiaMn1-gGgPO4(0.90≦a≦1.8, 0≦g≦0.5);Li (3-f) Fe2(PO4)3(0≦f≦2); LiaFePO4(0.90≦a≦1.8).

[0133] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; L1 is Mn, Al, or a combination thereof.

[0134] A positive electrode for a lithium secondary battery may include a current collector and a positive electrode active material layer formed on the current collector. The positive electrode active material layer may include a positive electrode active material and further include a binder and / or a conductive material.

[0135] The content of the positive electrode active material may be 90% to 99.5% by weight relative to 100% by weight of the positive electrode active material layer, and the content of the binder and conductive material may be 0.5% to 5% by weight, respectively, relative to 100% by weight of the positive electrode active material layer.

[0136] Al can be used as the current collector, but is not limited to it.

[0137] The negative electrode active material includes a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0138] The material capable of reversibly intercalating / deintercalating lithium ions is a carbon-based anode active material, which may include, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of crystalline carbon include graphite such as natural or artificial graphite, and examples of amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, and calcined coke.

[0139] As the substance capable of doping and undoping with lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material can be used. The Si-based negative electrode active material may be silicon, a silicon-carbon composite, SiOx (0 < x < 2), a Si-based alloy, or a combination thereof.

[0140] The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in a form in which amorphous carbon is coated on the surface of silicon particles.

[0141] The silicon-carbon composite may further contain crystalline carbon. For example, the silicon-carbon composite may include a core containing crystalline carbon and silicon particles, and an amorphous carbon coating layer located on the surface of the core.

[0142] The negative electrode for a lithium secondary battery includes a current collector and a negative electrode active material layer located on the current collector. The negative electrode active material layer contains a negative electrode active material and may further contain a binder and / or a conductive material.

[0143] For example, the negative electrode active material layer may contain 90% to 99% by weight of the negative electrode active material, 0.5% to 5% by weight of the binder, and 0% to 5% by weight of the conductive material.

[0144] As the binder, a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof can be used. When using an aqueous binder as the negative electrode binder, a cellulose-based compound capable of imparting viscosity can be further contained.

[0145] As the negative electrode current collector, one selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof can be used.

[0146] The electrolyte for lithium secondary batteries contains a non-aqueous organic solvent and a lithium salt.

[0147] The non-aqueous organic solvent acts as a medium through which ions involved in the electrochemical reaction of the battery can move.

[0148] The non-aqueous organic solvent may be a carbonate-based, ester-based, ether-based, ketone-based, or alcohol-based solvent, an aprotic solvent, or a combination thereof, and can be used alone or in a mixture of two or more.

[0149] Furthermore, when using carbonate-based solvents, cyclic carbonates and linear carbonates can be mixed and used together.

[0150] Depending on the type of lithium secondary battery, a separator may be present between the positive and negative electrodes. Such separators can be polyethylene, polypropylene, polyvinylidene fluoride, or multilayer films of two or more layers thereof.

[0151] The separator may include a porous substrate and a coating layer containing organic, inorganic, or a combination thereof located on one or both sides of the porous substrate.

[0152] The aforementioned organic material may include a polyvinylidene fluoride polymer or a (meth)acrylic polymer.

[0153] The inorganic material may include, but is not limited to, inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0154] The organic and inorganic materials can exist mixed together in a single coating layer, or they can exist in a form in which a coating layer containing organic materials and a coating layer containing inorganic materials are stacked on top of each other.

[0155] Although the present invention has been described above with limited embodiments and drawings, it goes without saying that the present invention is not limited thereto, and that various modifications and variations are possible within the equivalent scope of the technical concept of the present invention and the claims described below by persons with ordinary skill in the art to which the present invention pertains. [Explanation of Symbols]

[0156] 10: Inter-cell short-circuit detection system 100: Inter-cell short-circuit detection unit 110: Communications Department 120: Input section 130: Display section 140: Memory 150: Control Unit 200: Voltage measurement section 210: Probe 220: Probe Control Unit 230: Pressure sensor 300: Short Control Unit

Claims

1. A voltage measurement unit configured to include a probe that contacts a cell of a secondary battery and measures the voltage between cells; A short circuit control unit configured to control a short circuit between the cells; The voltage measurement unit is controlled to measure a first voltage between a first cell and a second cell of the secondary battery, the short circuit control unit is controlled to generate a short circuit between the first cell and the second cell, the voltage measurement unit is controlled to measure a second voltage between the first cell and the second cell, the short circuit control unit is controlled to remove the short circuit between the first cell and the second cell, the voltage measurement unit is controlled to measure a third voltage between the first cell and the second cell, and at least one of the first voltage, the second voltage, and the third voltage is used to determine whether there is a short circuit between the first cell and the second cell. A cell-to-cell short circuit detection unit configured as such; A cell-to-cell short circuit detection system for a secondary battery.

2. The cell-to-cell short circuit detection unit: Determines whether there is a short circuit between the first cell and the second cell based on whether the second voltage corresponds to a preset cell voltage reference. The cell-to-cell short circuit detection system for a secondary battery according to Claim 1.

3. The cell-to-cell short circuit detection unit: Determines whether there is a short circuit between the first cell and the second cell based on whether the difference between the first voltage and the second voltage corresponds to a preset cell voltage reference. The cell-to-cell short circuit detection system for a secondary battery according to Claim 1.

4. The cell-to-cell short circuit detection unit: Determines whether there is a short circuit between the first cell and the second cell based on whether the difference between the third voltage and the second voltage corresponds to a preset cell voltage reference. The cell-to-cell short circuit detection system for a secondary battery according to Claim 1.

5. The probe: Is configured in an "L" shape. The cell-to-cell short circuit detection system for a secondary battery according to Claim 1.

6. The probe: Is configured in a "V" shape. The cell-to-cell short circuit detection system for a secondary battery according to Claim 1.

7. The probe: Is configured in a "W" shape. The cell-to-cell short circuit detection system for a secondary battery according to Claim 1.

8. The voltage measurement unit: Adheres to one surface of the probe and is configured to measure the pressure applied to one surface of the probe. The device further includes a probe control unit configured to control the operation of the probe and to control the operation of the probe so that the probe contacts the cell at a pressure below a preset pressure. A short-circuit detection system between cells of a secondary battery according to claim 1.

9. The probe control unit, The operation of the probe is controlled so that the probe passes through the CMC hole of the can constituting the cell and contacts the cap plate. The inter-cell short-circuit detection system for a secondary battery according to claim 8.

10. The short-circuit control unit, This is characterized by adding a specific resistor between the first cell and the second cell to cause a short circuit. A short-circuit detection system between cells of a secondary battery according to claim 1.

11. A method driven by a secondary battery inter-cell short-circuit detection system, which includes a voltage measuring unit configured to include a probe that contacts the cells of the secondary battery to measure the voltage between the cells, and a short-circuit control unit configured to control a short circuit between the cells, The steps include controlling the voltage measuring unit to measure a first voltage between the first cell and the second cell of the secondary battery, The steps include controlling the short-circuit control unit to cause a short circuit between the first cell and the second cell, The steps include controlling the voltage measuring unit to measure the second voltage between the first cell and the second cell, The steps include controlling the short-circuit control unit to eliminate the short circuit between the first cell and the second cell, The steps include controlling the voltage measuring unit to measure the third voltage between the first cell and the second cell, The process includes a cell-to-cell short-circuit detection step that determines whether or not there is a short circuit between the first cell and the second cell using at least one of the first voltage, the second voltage, and the third voltage. A method for detecting short circuits between cells in a secondary battery.

12. The aforementioned inter-cell short-circuit detection step is: The presence or absence of a short circuit between the first cell and the second cell is determined by whether or not the second voltage corresponds to a preset cell voltage reference. The method for detecting inter-cell short circuits in a secondary battery according to claim 11.

13. The aforementioned inter-cell short-circuit detection step is: Determining whether there is a short circuit between the first cell and the second cell based on whether the difference between the first voltage and the second voltage corresponds to a preset cell voltage reference The method for detecting an inter-cell short circuit of a secondary battery according to claim 11

14. The inter-cell short circuit detection step is Determining whether there is a short circuit between the first cell and the second cell based on whether the difference between the third voltage and the second voltage corresponds to a preset cell voltage reference The method for detecting an inter-cell short circuit of a secondary battery according to claim 11

15. The probe is Characterized in that it is configured in an "L" shape The method for detecting an inter-cell short circuit of a secondary battery according to claim 11

16. The probe is Characterized in that it is configured in a "V" shape The method for detecting an inter-cell short circuit of a secondary battery according to claim 11

17. The probe is Characterized in that it is configured in a "human" shape The method for detecting an inter-cell short circuit of a secondary battery according to claim 11

18. The voltage measurement unit is Further configured to include a pressure sensor attached to one surface of the probe and configured to measure the pressure applied to one surface of the probe, and a probe control unit configured to control the operation of the probe The voltage measurement step of controlling the voltage measurement unit to measure the first voltage, the second voltage, and the third voltage between the first cell and the second cell is Characterized in that the operation of the probe is controlled by controlling the probe control unit so that the probe contacts the cell at a pressure below a preset pressure The method for detecting an inter-cell short circuit of a secondary battery according to claim 11

19. The voltage measurement step is Characterized in that the operation of the probe is controlled by controlling the probe control unit so that the probe passes through the CMC hole of the can constituting the cell and contacts the cap plate The method for detecting an inter-cell short circuit of a secondary battery according to claim 18

20. The step of controlling the short circuit control unit to generate a short circuit between the first cell and the second cell is Characterized in that the short circuit control unit is controlled to add a specific resistance between the first cell and the second cell The method for detecting an inter-cell short circuit of a secondary battery according to claim 11

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